According to documents obtained by the Ukrainian military and shared with The Guardian, Russia's military command foresaw Ukraine's August 6 incursion and failed to act on warnings from those in the region. Newsweek has contacted the Russian Ministry of Defense for comment on the reports.

Russia said on Friday that its army would regain control of its Kursk region "in a timely manner", declining to say how soon this could be achieved.

Russian commanders anticipated that Ukraine was planning an incursion into Kursk Oblast months before it occurred, the Guardian reported on Sept. 20, citing a collection of documents that Ukrainian soldiers said they had seized from abandoned Russian positions.

Russia warned the West and Ukraine on Friday of "disastrous consequences" if Kyiv moved against close Russian ally Belarus, making clear it would intervene to defend a country where it has deployed tactical nuclear weapons.

A close ally of President Vladimir Putin warned Western governments on Thursday that a nuclear war would ensue if they gave the green light for Ukraine to use long-range Western weapons to strike targets deep inside Russia.

European Union lawmakers on Thursday called to lift "restrictions hindering Ukraine from using Western weapons systems against legitimate military targets in Russia," a press release said. The restrictions hinder Ukraine’s ability to fully exercise its right to self-defence and leave Ukraine exposed to attacks on its population and infrastructure,